The present invention relates to a drive, and in particular to a variable-stroke and frequency drive. Still more particularly, the invention relates to a variable-stroke and frequency drive for use with ink-distributing cylinders of printing machines.
It is known from the prior art to provide arrangements for varying the stroke and frequency of movements of ink-distributing cylinders in printing machines. The drive in these prior-art arrangements makes it possible to adjust the amplitude of the distributing movement of the cylinder as well as the frequency of these movements. For this purpose the prior-art drive provides a pivotable guide plate with a groove into which a sliding block extends which is fixedly connected with a gear that is turnably mounted on the shaft of the ink-distributing cylinder. The amplitude of the cylinder movement is varied by pivoting the guide plate to vary its inclination, and the frequency of the movement of the cylinder can be adjusted by varying the transmission ratio of a continuously variable drive that cooperates with the gear.
However, the prior-art arrangement just described has various disadvantages. One of these is the fact that it is quite complicated in construction in that it requires separate drives for the variation of the stroke and for the variation of the frequency of the cylinder movements, and is therefore highly susceptible to malfunction. In addition it is difficult to adjust the two drives so that they properly cooperate with one another, and improper settings, resulting in improper operation of the ink distributing cylinder, are impossible to avoid.